I've Got +20 Reduced Armor Wtf?

I've checked if I get +20 Armor after unlocked the Warp-Touched Armour and I've seen that I have low Armor. Then I've checked it on the Rank 1 CSM and he had exactly +20 Armor. While I supposed to get +20 more Armor, I got -20 less. Wtf?

Edit: The problem was I have replaced Mark of Khorne with Shard of Steel which was giving +20 Armor. Well, issue has been resolved.

Wtf? Really? Then why they didn't changed the description? Because I thought I would get +20 Armor!!! Well, that doesn't problem as far as I am in the melee battle, but against shooters I am way too weak and only way to receive my life back is to hit someone! And why the hell they didn't nerfed the Eldar then?!